Modern optical systems, such as state of the art image projectors which are quite compact, rely on light sources with high light intensity. Image projectors are also increasingly being used in e.g. simulation systems, which require very sharp and bright images. With the known lamp technology, it very difficult to produce high brightness images from projectors, without having to use high power light sources. Today, similar brighness levels in projectors are obtained by high power Xenon lamps.
Most image projectors use ultra-high-pressure (UHP) lamps with a short arc gap. Lamps termed “short arc gap” typically have an arc gap in the range between 1.0 mm and 1.5 mm. The light emitted by short arc gap lamps has a much better light collection than light emitted by lamps with larger arc gaps, and thus a very good visible light efficiency. It is thus desirable to use lamps with an arc gap as short as possible in modern image projectors, in order to produce the brightest possible image.
Short arc gap lamps are, however, only available at comparatively lower power outputs (e.g. 1.0 mm at 150 W and 1.4 mm at 300 W). In order to produce high quality images by projectors, it is therefore known to arrange two or more short arc lamps in a system.
One such multi-lamp system utilizes an assembly of 4 short arc gap lamps, in a quadratic configuration, each lamp having a parabolic reflector with a condenser lens that focuses the light into a common light guide. This assemly is able to gain 1.5 times the flux of a single lamp system. Typical lamp arc gap for such system is 1.0 mm to 1.3 mm.
It is therefore a need for a multi-lamp system that produces a flux level that is equal to or better than known systems, but with fewer lamps, thus yielding reduced material cost, manufaturing cost and operating costs, reduced power consumption and reduced product temeperature, compared to known systems.
The invented system may utilize shorter arc gap lamps than the presently known technology, thus producing a better image performance.